Thunder five

Anyone know how much a one off cut-a-way thunder five revolver would be worth?(its the 45-410) I know they only made one. I have a 45-70 and a 45-410. I have 102 drop in cylinders i have 9mm 357mag 38sp 30 luger 30 mauser 22lr 22mag and 32 sw. i have know idea what its worth. please help.